For those of us who have cats that we let outside, we often wonder where they go when we can’t see them. I know I have personally imagined strapping a camera onto my cat and watching his adventures throughout the day. Scientists in the United States, Australia, and New Zealand have teamed up with civilians and their cats to do just that. Scientists reach out to citizens with house cats that go outside. The cats had a camera and GPS device strapped onto them for about a week at a time and were let outside as they normally would. The camera gave the scientists and pet owners a cat eye view of their pet’s domain and the GPS let them see exactly where the cats went. The regular area in which animals-such as cats- travel to find food, shelter, mates, etc. is referred to as a home range. The purpose of tracking the home range of domestic cats is for ecologists to be able to better understand where cats go when they go outside and to also study how they impact the ecosystem. Studies have show that domesticated cats have a negative impact on biodiversity in their environment, especially the levels of small mammals and birds. Ashley Gramza in “Understanding Public Perceptions of Risk Regarding Outdoor Pet Cats to Inform Conservation Action.” discusses some of the ways that cats can impact biodiversity. According to Gramza, behaviors of the owner with the cat and the cat’s general attitude will impact how they hunt and interact with the outside environment when they are left outside to roam. In the article it also supports the idea that the more pet owners and other citizens that are educated on cat behavior, the better we can help keep cats safe when they roam outside and put plans into place to conserve the wildlife.
This week in lab we used data compiled from the cats in New Zealand, Australia, and the United States to calculate the average home ranges per country. Using the data from movebank.org for Felis catus, we each picked 15 random cats per country to calculate home range. (Personally, I picked the cats based on how cute their names were but my fellow students all had their own criteria for cat selection.) Once we picked the cat we copied the data from movebank to Google Earth to be able to better see the home ranges of the cats and to be able to plot the area of the home range. Using tools on Google Earth to get the area, we copied the area into Earth Point to get the area in hectare. The data I found is shown below:
As shown in the graph above, the United States had the highest average home range per hectare, New Zealand had the second highest, and Australia had the lowest. While calculating the data in Google Earth, we were able to see the landscape and landmarks within the area the cat lived in. For most cats- no matter what country they were in- they lives in very suburban areas. New Zealand was the most spread out in terms of cities and houses, the United States had a good mix. To see test if there was a significant difference between the the data, we ran an ANOVA analysis. With the ANOVA it will calculate the p-value which we can then compare to the alpha value of 0.05. The ANOVA came back with a P-value that was higher than 0.05. When the p-value is greater than alpha, there is a significance between data. This means there is significant difference between the home ranges in the US, New Zealand, and Australia. What surprised me the most about the data is that in Australia the houses are very, very close together. There was very little yard space and green spaces in residential areas. It was large areas of nothing but houses right next to each other. I believe the high density of residential areas in Australia account for why the cats in Australia had the lowest average home range. In the United States there was more forest area mixed in with the suburban areas, which would mean more area for the cats to possibly hunt or find mates in the surrounding area. New Zealand had a mix of highly populated areas and rural areas. Most of the cats in New Zealand lived in the suburban areas.
Different factors could influence the way cats interact with their environments and their home ranges. Biotic factors could include other cats or predators in the area. That could cause competition between cats. Some abiotic factors could include housing developments, roads, etc. Anything that could serve as a roadblock to the cats getting places or hunting. The home ranges of the cats I sampled mostly stayed within close range to their homes. From this I would predict that the overall biodiversity in the cats’ home ranges are less impacted in highly populated areas like Australia. In the United States where there is more forest area, the cats would probably impact the biodiversity more because there is more prey for them.
We were asked this week to take our data and observations from Google Earth and to think as if we were an urban land developer. Specifically what changes we would make to the landscape of the environments in which the cats lived, while also keeping the local wildlife in mind. Based on my findings I would try to modify more of the areas to mimic the suburban areas of the United States. Specifically Australia where there was little to no green spaces and the home ranges of the cats were half of what they are in the US.
References:
Gramza, Ashley, et al. “Understanding Public Perceptions of Risk Regarding Outdoor Pet Cats to Inform Conservation Action.” Conservation Biology, vol. 30, no. 2, Apr. 2016, pp. 276–86, doi:10.1111/cobi.12631.
Aurora Ecology 